1. Field of the Invention
This invention relates to a drain valve or drain cock and more particularly, an improved drain valve used for draining fluids of any type and useful in applications for draining fluid such as oil, gas, air, water, antifreeze, etc. Further, the invention finds use as a replacement valve for existing drain valves, the invention being easier to operate as will be determined by the disclosure of the preferred embodiments and appended claims.
2. Description of the Prior Art
As is well known, proper maintenance of various machinery, such as airplanes, automobiles, boats, etc., using such fluids as lubricating oils, gasoline, diesel, antifreeze, water, etc., requires the frequent drainage of such fluids to determine, by inspection, the conditions of the machinery and the fluid, and for scheduled and non-scheduled replacement of the fluid. Further machinery such as an air compressor tank requires drainage of unwanted built-up fluids such as water or other fluid lines having an unwanted concentration of air that need bleeding off.
A drain plug, requiring removal, is commonly used in most instances mentioned above, whereas in other instances, drain valves requiting the operator to rotate a threaded valve to open or close it. In both instance, use of some type of hand held tool is required to assist in the removal or opening of the drain plug or drain valve.
Other known types of drain valves are of the push-pull type having a resilient spring forcing the closure of the valve, the valve being opened by the operator pushing or pulling an actuator to overcome the force of the spring. William Beardsley, discloses such a push-pull type of valve in U.S. Pat. No. 218,698, patented on Aug. 19, 1879. Beardsley's valve found use as a bottle stopper, and contemplated use within a faucet, and uses the force of the spring to hold the valve in a closed position. Beardsley's valve comprised a tubular shaped valve stem having an closed end, closed by a plug, extending into the bottle and an inlet through the side of the valve stem extending into the bore of the tube for allowing fluid to flow through the tube to an open end of the valve stem external to the bottle. The spring forces the inlet up into the neck of the bottle to prevent fluid from flowing from the tube. A seal formed by an elastic flange is disposed around the plug and is adapted to fit snugly against the inside of the bottle to prevent the fluid from passing the elastic flange until the valve is opened by pushing the open end of the valve stem in a direction opposite the force of the spring. Beardsley's valve/stopper has a problem in that the elastic flange needed to be resilient enough to allow the stopper to be inserted into and removed from the bottle. Accordingly, there was no means provided to ensure the stopper remain seated in the neck of the bottle, and lacked means to maintain the valve in an open position absent the pressure applied thereto by the operator.
The Quickly Disassembled Inflation and Relief Valve disclosed by H. H. Mackal in U.S. Pat. No. 2,855,946 also uses the force of a spring to close the valve to prevent fluid, i.e., air from passing through an inlet disposed into the side of the valve stem and extending into the tube formed therein. Mackal's valve is opened by pressing the open end of the valve stem against the force of the spring. Mackel's valve differs from Beardsley's in that Mackal's valve includes a valve body having an end that extends into a flexible tube, the end having conical zones to seal the valve against the inner surface of the flexible tube. The inlet to the Mackal's valve stem is covered by the conical zoned end of the valve body and air is prevented from reaching the inlet by a rubber-like annular washer which is recessed into the conical zoned end of the valve when in a closed position. A cylindrical portion of Mackal's valve body that is disposed to the outside of the flexible tube through which the valve stem travels has a slot allowing for a pin in the side of the valve stem to travel when opening the valve. The cylindrical portion also has a notch therein where the operator seats the pin to maintain the valve in a closed position to prevent the valve from being opened accidentally. Accordingly, Mackal's valve also fails to provide any means, absent the operators force applied to the open end of the valve stem, for holding the valve in an open position.
The Hand-Held Drain Valve Operating Receptacle disclosed in U.S. Pat. No. 3,198,016 to R. H. Poorman comprises a tubular valve body in which a valve stem is seated. A spring in provided which fits over the valve stem and within the tubular body of the valve body. Poorman's valve stem differs from that of Beardsley and Mackal, in that the fluid, i.e. gasoline, does not flow through the Poorman's valve stem because it is not tubular and has no inlets or outlets. Poorman's tubular valve body comprises a threaded section adapted to be threaded into the gas tank of an aircraft. An inlet is provided on the side of the valve body next to the threaded end. Fluid is prevented from passing from the inlet to the outlet portion of the valve body by an O-ring, around one end of the valve stem, forced into a sealed position by the spring. In order to open the Poorman's drain valve a metal rod has to be inserted through the outlet portion of the valve body in order to apply a force opposite the force of the spring to move the O-ring past the inlet portion of the valve body. Accordingly, Poorman's drain valve does not have any means for holding the valve in an opened position. Poorman's outlet portion of the valve body has a hexagonal shape to allow for the use of a tool so that the body may be screwed and tightened into the gasoline tank, and has openings in the hexagonal portion for attaching a wire secured to the aircraft's wing to prevent valve body from rotating once installed.
The Rotatable Bayonnet-Type Coupling disclosed by Oetiker in U.S. Pat. No. 3,858,910 comprises a spring biased valve having an arrangement for locking open a valve, wherein locking pins 14 attached to the valve stem 17 slide through groove 16 into slot 15 and then, as the valve stem in rotated clockwise, lock into notch 18. Once the valve is rotated counter clockwise to align pins 14 with slots 16 the spring 11 will force the valve into a closed position.
Laipply, et al. disclose in U.S. Pat. No. 4,745,894 an Oil Drain Valve having a tubular housing with a threaded end to be threaded into a conventional drain hole of an oil pan, a central portion of hexagon shape for reception of a tool to aid in the insertion of the valve body into the oil pan, and an external cylindrical external end. The external cylindrical end includes a beveled end and a locking annular ball groove for attaching a cap or a conduit end fitting. A tubular valve steam has an open end and a closed end. Inlets are provided in the side of the valve stem near the closed end. Further, the closed end of the valve stem has a lip which must be deformed to allow the valve stem to be inserted through the valve body, and thereafter the lip is swaged to a radial position to support a seal and prevent the valve stem from being removed from the valve body. A spring is provided between the valve stem and the inner portion of the tube of the valve body to force the valve into a closed position. In order to open the valve the conduit end fitting has a probe therein to displace the valve stem into the open position when the conduit end fitting is attached to the external cylindrical end of the valve body. This oil drain valve has several deficiencies, such as having a deformable lip subject to breakage due to fatigue of the material forming the valve stem which will cause to valve to open when not desired. Further, a tool must be inserted, by the operator, into the valve opening to depress the valve stem in order to open the drain valve and a special tool, i.e. the conduit end fitting, is required in order hold the valve in an open position, absent the force proved by the operator.
The Oil Drain Valve Assembly disclosed in U.S. Pat. No. 5,096,158 to Douglas Burdick, et al. comprises a tubular assembly, for draining oil therethrough, adapted to be threaded into an engine crankcase and a sleeve assembly fit over a cylindrical section of the tubular assembly in a slidable fashion, the sleeve assembly having what amounts to a "plug" formed therein. There are a pair of diametrically opposed "J" slots provided on the side of the sleeve assembly for guiding the sleeve assembly along a pair of pins protruding from the side of the cylindrical section of the tubular assembly. The valve is closed by pushing the sleeve assembly upwards and rotating it clockwise to lock it into a closed position. To open the drain valve, the sleeve assembly is rotated counter clockwise and pulled downward thereby pulling the "plug" from the opening in the cylindrical end of the tubular assembly. A disadvantage of this oil drain valve is that there are no means provided to bias the valve into a closed position should the sleeve assembly accidentally be caused to open, thereby resulting in a loss of oil and damage to the engine. Likewise, should the pins become damaged so as to fail to hold the sleeve in position the oil will accidentally drain out of the engine.
The Slidable Type Drain Cock discussed in U.S. Pat. No. 2,506,722 by William J. Kuehn, et al. comprises a tubular housing comprising a threaded section adapted to be threaded into a component of an aircraft and a hexagonal nut section for assisting in the tightening or loosening of the tubular housing. A valve stem having a length greater than that of the tubular housing extends through both ends of the tubular housing. The end of the valve stem that extends from the threaded end of the tubular housing and into the aircraft component has a closed end comprising an annular groove for reception of an O-ring. The O-ring seats into the opening of the tubular housing through which the valve stem protrudes in order to seal the drain cock and aid in retaining the valve stem in assembled combination with the tubular housing when the drain cock is in a closed position. The valve stem comprises a drainage bore, and inlets are provided in the side of the valve stem adjacent the annular groove at closed end thereof to allow the fluid to drain into and through the drainage bore when the valve stem is depressed inwardly thereby lifting the O-ring from the seat in the tubular housing allowing the fluid to reach the inlets. A crossbar having inturned ends is provided at the outlet end of the valve stem to assist the operator in opening the drain cock. Further, when the drain cock is fully opened, the operator can turn the crossbar so that the inturned ends sit on the corners of the hex nut, or in grooves provided in the hex nut, so as to hold the drain cock in the open position. A spring, provided over a portion of the valve stem adjacent the crossbar and extended into a portion of the tubular housing, urges the valve stem into a closed position and the force of the spring must be overcome in order to open the drain cock. This drain cock has several disadvantages in that the spring is open to the environment and therefore subject to elements that can cause it to corrode and break. Further, the inturned ends of the crossbar can become damaged and therefore fail to hold the drain cock in the open position. Additionally, it is difficult to replace the spring because the drain cock is not easily disassembled.